Process for the manufacture of magnesium



Ell

Patented July' 12, 1932 UNITED s'rA'rEs mm canons. season, or car,nuance PROCESS BOB THE onscreen or ennsrou Ito Drawing; Application andma in, was, serial No. states, and in German time 1, area It is a knownfact that in the electrolytic manufacture of magnesium from magneslumchloride, that on the one hand, the electrce lytic yield of theoperation, that is, the amount of magnesium obtained per unit quantityof electric current, will rapidly diminish when the magnesium'chloridecon tains traces of water, and on the other hand, the complete drying ofmagnesium chloride is a very diflicult expensive operation,

it has been further-observed that a min ture oi potassium chloride andmagnesium chloride in the proportion out two or three molecules oi thefirst to one molecule of the second, may he treated by electrolysis witha satisfactory eficiency, even it it contains 1 to it per cent of water,but this eficiency will gradually diminish when the molecular proportionof potassium chloride to the magnesium chloride exceeds 3 to l, theercentage oil water remainin within the a eve-men tioned limits. @n t econtrary, with the lat ter mixture, a very good yield is obtained whenthe percentage of water is below l per cent,

The present invention has for its object to obviate the drawbacksspecified in the first paragraph, and to. utilize the remarkable effectsabove mentioned. 1

For this purpose, there'is prepared in the iirst place an incom leteldehydrated mixture of potassium c lori e an magnesium chloride, in theproportion of three molecules of the first-mentioned chloride for atleast one molecule of the second, and this mixture is treated byelectrolysis until the proportion of potassium chloride exceeds threemolecules for one molecule of magnesium chloride, due to theprecipitation of the magnesium. flhe greater artof the water containedin this mixture as now been eliminated. The

said mixture, which is v practically anhycircus, is then subjected to asecond electrolysis and this is efiected with an excellent yield. a Itis observed that the quantlty of electric currentconsumed during thesetwo electro lytic treatments is less than the quantity which would havebeen consumed in the first place during a preliminary heating of themixture in order that it will be completely dehydrated, and less thanthe amount which would have been used during an eficient electrolysis oithe dry mixture,

It advantageous to sheet the two electrolytic treatments in two diderenttanks or vets, and in this manner, a vat which is employed for the firstelectrolysis will serve to supply several vats used for the second elec'trolysie,

The mixture used in the first electrolysis is preferahly dehydrated inpart, by one or the other ot the following processes,

1. By adding, in the hydrated state, magnesium chloride or a mixture outmagnesium chloride and potassium chloride, or carnal lite, in a gradualmanner and in relatively small quantities to a relatively large liquidmass of magnesium chloride or a 'uaiuture of dehdyrated magnesiumchloride and pe tassium chloride, as specified in the pending U. S.application No. 4%,63? dated March 3t, 1930 in the name of Madame ElizaLacell, en titled: Process for the dehydration of car nadllite andparticularly ct magnesium chicin e.

2. By adding, durin the dryin oi mag nesium chloride, peter-slumchloridg ohteined from the second electrolysis, in such manner that thepotassium chloride will follow a closed circuit and will not exceed theper centa e desired for the first electrolyte as s eci ed in the endingapplication filed in S.A, by. P. C hmescasse, on behalf of TheMagnesium; Production Go; Ltd. on April 14, 1930, entitled: Improvementsin process tilt lid

for the manufacture of magnesium, Serial Before the said mixture reachesthis than 2% of water; proceeding with a first electrolysis of thementioned mixture in such a way as to obtain a mixture which ispractically anhydrous and containing more than three molecules ofpotassium chloride for one of magnesium chloride, and then to proceedwith a second electrolysis of the mixture obtained as a result of thefirst electrolysis.

2. Process according to claim 1 in which the mixture obtained at theend'of the first electrolysis is conveyed into a separate electrolyticapparatus for the second electroly- SlS.

3. Process according to claim 1 in which the mixture obtained at the endof the first electrolysis is distributed among a plurality ofelectrolytic cells for carrying out the second electrolysis.

4. Process for the production of mag- ALFRED CLAUDEQJESJSUP.

nesium by electrolysis, consisting in grad- 'ually ad ing small massescontaining, at

least partially hydrated magnesium chloride, to a large mass containingsubstantially anhydrous magnesium chloride, one at least of saidmaterials containing potassium chloride, so as to obtain a mixture ofpotassium chlo- ,;,r1de and magnesium chloride containing less thanthree molecules of the first to one of the in such amounts as to obtaina mixture of otassium chloride and magnesium chlorlde containing lessthan three molecules of the first to one of the second and at the most2% water; then proceeding with a first electrolysis of theaforesaid'mixture so as to obtain a practically complete dehydration,and to form an electrolyte containing at least three molecules ofpotassium chloride to one of magnesium chloride; and then proceedingwith a second electrolysis of the mixture obtained from the firstelectrolysis, and introducmg at least in. part, the mixture remaining atthe end of the second electrolysis, into the process of dehydration ofthe magnesium chloride constituting the first stage of the process.

6. A process for the electrolytic manufacture of magnesium whichcomprises first preparing an incompletely dehydrated mixture ofpotassium chloride and magnesium chloride in the proportion of two tothree molecules of the former to one of the latter; subjecting suchmixture, in a molten state to a have signed this

